DevTools: Support asynchronous call stacks on backend.

LayoutTests/inspector/debugger/debugger-activation-crash2.html

 <script src="../../http/tests/inspector/inspector-test.js"></script>
 <script src="../../http/tests/inspector/debugger-test.js"></script>
 
 <script>
 var closures = [];
 function makeClosure() {
     var v1, v2, v3, v4, v5, v6, v7, v8, v9, v10; // Make a lot of potentially captured variables.
     return function () { 
         var x = v1; // But only capture one in optimizing compiles.
         return x;
@@ skipping 22 matching lines @@
 
     function step2(sourceFrame)
     {
         InspectorTest.addResult("Script source was shown.");
         InspectorTest.setBreakpoint(sourceFrame, 8, "", true);
         InspectorTest.runTestFunctionAndWaitUntilPaused(step3);
     }
 
     function step3(callFrames)
     {
-        InspectorTest.captureStackTrace(callFrames, true);
+        InspectorTest.captureStackTrace(callFrames, null, { dropLineNumbers: true });
         InspectorTest.completeDebuggerTest();
     }
 }
 
 window.onload = runTest;
 </script>
 
 <p>
 Tests for a crash when paused at a breakpoint caused by inaccurate Activation records.
 <a href="https://bugs.webkit.org/show_bug.cgi?id=57120">Bug 57120</a>
 </p>